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Background and Aims Early defoliation (ED) can reduce vine yield and improve fruit composition in vigorous vineyards. The objective of this study was to test the effectiveness of this technique for the Vitis vinifera (L.) cultivar Tempranillo under the temperate warm and semi‐arid climatic conditions of south‐eastern Spain. Methods and Results Four treatments were applied over three seasons to drip‐irrigated vines, planted with rows orientated north–south and shoots vertically positioned. Non‐defoliated vines (control) were compared with vines defoliated either just before anthesis (phenological stage H, treatment ED) or at fruitset [phenological stage J, treatment late defoliation (LD)]. In the fourth treatment, only the leaves facing east were removed at phenological stage H (treatment east ED). In the fourth experimental season, all treatments were managed similarly. Defoliation did not reduce fruitset but reduced berry mass, particularly in the ED and the LD treatments. Defoliation, however, had a cumulative negative effect on vine bud fertility. Even in the fourth experimental season, the yield of the ED treatment was 18% lower than that of the control. Both the ED and particularly the LD treatments increased berry total soluble solids (TSS) and phenolic concentration. The effect of leaf removal on berry TSS and phenolic concentration was not significant in the east ED treatment. Conclusions Defoliation at fruitset was the most effective treatment for increasing berry phenolics and TSS while maintaining must acidity. Growers should take into account, however, the important yield penalty because of defoliation, particularly in the mid‐term. Significance of the Study Early defoliation of Tempranillo grapes growing in semi‐arid and temperate climates needs to be applied with caution and probably limited to specific seasons while consecutive defoliations should be avoided.

Background and Aims Previous research has investigated widely the effects of irrigation application in red winegrape cultivars; however, white grape cultivars have been the subject of a lesser number of field trials. An experiment was undertaken for three seasons in a drip‐irrigated, cv. Muscat of Alexandria/161‐49C vineyard to define the most sustainable irrigation strategy for white winegrapes in eastern Spain. Methods and Results The treatments were as follows: (i) Control, irrigated at 100% of estimated crop evapotranspiration (ETc) for the entire season; (ii) sustained deficit irrigation (SDI), irrigated at 50% of Control; (iii) early deficit (ED), where pre‐veraison irrigation was withheld, followed by 100% ETc; and (iv) late deficit (LD), irrigated as for the Control until veraison and thereafter at 25% ETc until harvest. Yield in ED and LD was reduced 25 and 15%, respectively, compared with that of Control. Yield under SDI did not differ significantly from that of the Control and was similar to that of the ED and LD treatments. All the deficit irrigation treatments had some carry‐over effects because of a significant decrease in shoot fruitfulness and in bunch mass due to smaller berries. The ED treatment, however, led to a greater reduction in berry growth compared with that of LD. Full irrigation increased pruning mass and leaf area mainly due to larger secondary shoots, and besides delayed grape ripening. Conclusions The SDI treatment resulted in the greatest water use efficiency, ensuring the high yield potential of the cultivar, providing that a threshold value of water stress integral of 35 MPa day during the periods from anthesis to veraison and from veraison to harvest was not surpassed. In addition, it favoured an improved grape composition, particularly in terms of grape sugar accumulation. Significance of the Study Sustained deficit irrigation at 50% of ETc should be applied where water is scarce or expensive, paying attention to possible carry‐over effects if water withholding has to be continued for more than three seasons.

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Small berries are considered to produce the best red wines as berry size determines the skin to pulp ratio and may affect wine composition. However, contrasting results have been reported about this postulate. In this context, the aim of this work was to assess the influence of berry size on grape compositional attributes in ‘Tempranillo’ grapevines under different irrigation, crop load and defoliation regimes. Grapes were collected from different experiments performed during three years in a ‘Tempranillo’ vineyard (Valencia, Spain). Grape size distribution was assessed and several traits were measured for each size category: number of seeds, seed and skin weight, total soluble solids, titratable acidity, pH, total phenolic index and anthocyanin concentration. Berry size exerted a significant effect on grape composition; smaller berries having higher sugars and anthocyanins concentrations. However, irrigation, crop load and defoliation also affected these compositional traits, producing greater berries with similar traits than those smaller, but coming from rain-fed and not defoliated treatments. Depending on the field practices applied, grape compositional attributes can be modulated for a given berry size. Therefore, wineries can use berry size classification for selecting those from a given size for making different wine styles.